Intake manifold butterfly's - surge air intake manifold plenum

Hey Mark, long time, Yes, this is a big problem with these engines. Let's hope you are lucky, and no valves have been damaged. With it apart I would do a compression test to see if #6 is damaged before you reassemble it. If the compression is low, you will need to do a valve job. The part that has fallen apart is the intake running velocity control valve. (They needed to use Loctite thread lock, opps!) Make sure you don't have any open fuel lines when doing the test. Also, I have included how to reassemble the intake with torque specs. You will need to get a new/used intake because I don't think they service that part separately. Check out the diagrams (below). Let us know what happens and please upload pictures or videos of the problem.

Have heard of it at least once on another high mileage engine. The butterflies are supposed to stay centered, but the shaft wears the housing a bit and will let them drift, then it starts flexing the shaft and the screws work loose. BMW has a similar issue on one of their intake systems for much the same reason. I don't think they make the butterflies available yet, but I've made similar butterflies out of throttle body parts. Or if you, have you-pull it handy you might score a complete intake to go over before you install it. To keep the screws in place you could use the old trick I did on race cars. Take the shaft and use a countersink to give each screw hole a chamfer. Now set all the butterflies in place, close them tight so they stay centered, install new screws with red Loctite. Tighten them good. Wait about a day and use a C clamp to flatten the tip of the screw into the chamfer to lock it in.